AND LOWER EGYPT. 367

By Reaumur's, the difference was 3°|, the
mean heat 230!.

During these 21 davs the wind varied from the
N. E. to the N. blowing most frequently from the
latter point, from which it never deviated toward
the W.

It is well known, that land winds never blow
with an equality of force, and continued unifor-
mity ; but there is no country, perhaps, where,
they are more unequal and interrupted, than at
Cairo and in all Upper Egypt; this country being
nothing but a stripe of land, confined between
two chains of lofty mountains, that break the force
and direction of the winds ; which are often driven
into the narrow passes of these mountains, whence
they rush out with violence, and a whirling mo-
tion, that very frequently raises columns of sand
in the plains, resembling water-spouts.

It may be remarked also, from both the pre-
ceding tables, and this is a constant observation,
almost without an exception, which I made du-
ring my residence in Cairo and Upper Egypt, that
early in the morning the sky is never free from
clouds, more or less numerous, and more or less
dense, which fly along rapidly, though frequently
there is no wind at the time perceptible on the
surface of the earth. In the course of the morn-
ing these clouds disperse, as the sun increases its
height above the horizon. In general, too, the

wind